Use Stop Point location find with a GPS co-ordinate. The docs aren’t qutte right, the syntax is…
$strTFLurl = "https://api.tfl.gov.uk/StopPoint?lat=" . $row->fpNorthing . "&lon=" . $row->fpEasting . "&stopTypes=NaptanPublicBusCoachTram&radius=800&useStopPointHierarchy=True&returnLines=True&" . ApiConfig::TFLAPISUFFIX;
It’s SLOW so you will need to collect and cache the data if you want to use it more than once.
To get the list of stopTypes use https://api.tfl.gov.uk/StopPoint/Meta/stoptypes?app_id=&app_key=
However, it’s not clear (to me, sorry) from the question if what you actually want is the list of stations (in order) on the Central line, which is